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Re: [Qemu-devel] scp during migration with vhost fails
From: |
Jason Wang |
Subject: |
Re: [Qemu-devel] scp during migration with vhost fails |
Date: |
Tue, 26 Feb 2013 14:41:03 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 |
On 02/25/2013 06:01 PM, Michael S. Tsirkin wrote:
> On Mon, Feb 25, 2013 at 02:11:44PM +0800, Jason Wang wrote:
>> On 02/25/2013 01:57 PM, Jason Wang wrote:
>>> On 02/24/2013 05:54 AM, Michael S. Tsirkin wrote:
>>>> On Sat, Feb 23, 2013 at 10:49:29PM +0200, Michael S. Tsirkin wrote:
>>>>> On Fri, Feb 22, 2013 at 11:33:53PM +0800, Jason Wang wrote:
>>>>>> On 02/21/2013 07:23 PM, Michael S. Tsirkin wrote:
>>>>>>> On Thu, Feb 21, 2013 at 05:57:04PM +0800, Jason Wang wrote:
>>>>>>>> On 02/21/2013 12:48 AM, Michael S. Tsirkin wrote:
>>>>>>>>> On Wed, Feb 20, 2013 at 04:23:52PM +0200, Michael S. Tsirkin wrote:
>>>>>>>>>> On Fri, Feb 01, 2013 at 06:03:32PM +0800, Jason Wang wrote:
>>>>>>>>>>> Hello all:
>>>>>>>>>>>
>>>>>>>>>>> During testing, I find doing scp during migration with vhost fails
>>>>>>>>>>> with
>>>>>>>>>>> warnings in guest like:
>>>>>>>>>>>
>>>>>>>>>>> Corrupted MAC on input.
>>>>>>>>>>> Disconnecting: Packet corrupt.
>>>>>>>>>>> lost connection
>>>>>>>>>>>
>>>>>>>>>>> Here's the bisect result:
>>>>>>>>>>>
>>>>>>>>>>> Commit a01672d3968cf91208666d371784110bfde9d4f8 kvm: convert to
>>>>>>>>>>> MemoryListener
>>>>>>>>>>> API is the last commit that works well.
>>>>>>>>>>>
>>>>>>>>>>> With commit 04097f7c5957273c578f72b9bd603ba6b1d69e33 vhost: convert
>>>>>>>>>>> to
>>>>>>>>>>> MemoryListener API, guest network is unusable with warning of "bad
>>>>>>>>>>> gso type"
>>>>>>>>>>>
>>>>>>>>>>> With commit d743c382861eaa1e13f503b05aba5a382a7e7f7c vhost: fix
>>>>>>>>>>> incorrect
>>>>>>>>>>> userspace address, guest network is available, but scp during
>>>>>>>>>>> migration may
>>>>>>>>>>> fail.
>>>>>>>>>>>
>>>>>>>>>>> Looks like the issue is related to memory api, any thoughts?
>>>>>>>>>>>
>>>>>>>>>>> Thanks
>>>>>>>>>> Tried to reproduce this for a while without success.
>>>>>>>>>> Which command line was used?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> MST
>>>>>>>>> Could be we are not syncing all that we should?
>>>>>>>>> Does the following hack make the problem go away?
>>>>>>>>>
>>>>>>>>> diff --git a/hw/vhost.c b/hw/vhost.c
>>>>>>>>> index 8d41fdb..a7a0412 100644
>>>>>>>>> --- a/hw/vhost.c
>>>>>>>>> +++ b/hw/vhost.c
>>>>>>>>> @@ -69,6 +69,8 @@ static int vhost_sync_dirty_bitmap(struct vhost_dev
>>>>>>>>> *dev,
>>>>>>>>> hwaddr end_addr)
>>>>>>>>> {
>>>>>>>>> int i;
>>>>>>>>> + start_addr = 0x0;
>>>>>>>>> + end_addr = ~0x0ull;
>>>>>>>>>
>>>>>>>>> if (!dev->log_enabled || !dev->started) {
>>>>>>>>> return 0;
>>>>>>>>>
>>>>>>>> Still can reproduce with this. From the bisect result, the vhost dirty
>>>>>>>> bitmap sync itself looks ok but something wrong when converting to
>>>>>>>> memory listener.
>>>>>>> Reading the code carefully, I found two bugs introduced during
>>>>>>> this conversion. Patch below, could you please try?
>>>>>>>
>>>>>>> vhost: memory sync fixes
>>>>>>>
>>>>>>> This fixes two bugs related to memory sync during
>>>>>>> migration:
>>>>>>> - ram address calculation was missing the chunk
>>>>>>> address, so the wrong page was dirtied
>>>>>>> - one after last was used instead of the
>>>>>>> end address of a region, which might overflow to 0
>>>>>>> and cause us to skip the region when the region ends at
>>>>>>> ~0x0ull.
>>>>>>>
>>>>>>> Signed-off-by: Michael S. Tsirkin <address@hidden>
>>>>>>>
>>>>>>> ---
>>>>>>>
>>>>>>> diff --git a/hw/vhost.c b/hw/vhost.c
>>>>>>> index 8d41fdb..dbf6b46 100644
>>>>>>> --- a/hw/vhost.c
>>>>>>> +++ b/hw/vhost.c
>>>>>>> @@ -55,7 +55,7 @@ static void vhost_dev_sync_region(struct vhost_dev
>>>>>>> *dev,
>>>>>>> ffsll(log) : ffs(log))) {
>>>>>>> ram_addr_t ram_addr;
>>>>>>> bit -= 1;
>>>>>>> - ram_addr = section->offset_within_region + bit *
>>>>>>> VHOST_LOG_PAGE;
>>>>>>> + ram_addr = section->offset_within_region + addr + bit *
>>>>>>> VHOST_LOG_PAGE;
>>>>>>> memory_region_set_dirty(section->mr, ram_addr,
>>>>>>> VHOST_LOG_PAGE);
>>>>>>> log &= ~(0x1ull << bit);
>>>>>>> }
>>>>>>> @@ -94,7 +94,7 @@ static void vhost_log_sync(MemoryListener *listener,
>>>>>>> struct vhost_dev *dev = container_of(listener, struct vhost_dev,
>>>>>>> memory_listener);
>>>>>>> hwaddr start_addr = section->offset_within_address_space;
>>>>>>> - hwaddr end_addr = start_addr + section->size;
>>>>>>> + hwaddr end_addr = start_addr + section->size - 1;
>>>>>>>
>>>>>>> vhost_sync_dirty_bitmap(dev, section, start_addr, end_addr);
>>>>>>> }
>>>>>>>
>>>>>> I can still reproduce the issue with this patch.
>>>>> Yes it's still wrong. We need the following on top.
>>>>> Could you try please?
>>>>>
>>>>> diff --git a/hw/vhost.c b/hw/vhost.c
>>>>> index dbf6b46..c324903 100644
>>>>> --- a/hw/vhost.c
>>>>> +++ b/hw/vhost.c
>>>>> @@ -29,7 +29,7 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
>>>>> uint64_t end = MIN(mlast, rlast);
>>>>> vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
>>>>> vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
>>>>> - uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
>>>>> + uint64_t addr = 0;
>>>>>
>>>>> if (end < start) {
>>>>> return;
>>>> Sorry, scratch that last one, sorry.
>>>> This should be the right thing, I think: on top of
>>>> 'vhost: memory sync fixes'.
>>>>
>>>> diff --git a/hw/vhost.c b/hw/vhost.c
>>>> index dbf6b46..72c0095 100644
>>>> --- a/hw/vhost.c
>>>> +++ b/hw/vhost.c
>>>> @@ -53,9 +53,10 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
>>>> log = __sync_fetch_and_and(from, 0);
>>>> while ((bit = sizeof(log) > sizeof(int) ?
>>>> ffsll(log) : ffs(log))) {
>>>> - ram_addr_t ram_addr;
>>>> + hwaddr ram_addr;
>>>> bit -= 1;
>>>> - ram_addr = section->offset_within_region + addr + bit *
>>>> VHOST_LOG_PAGE;
>>>> + ram_addr = addr + bit * VHOST_LOG_PAGE -
>>>> + section->mr->offset_within_address_space;
>>> should be section->offset_within_address_space
>>>> memory_region_set_dirty(section->mr, ram_addr,
>>>> VHOST_LOG_PAGE);
>>>> log &= ~(0x1ull << bit);
>>>> }
>>>>
>>>>
>>> Still can reproduce. An interesting thing is after I chage the
>>> section->offset_within_address_space to section->mr->ram_addr[1]. I
>>> can't reproduce the issue. I haven't read all the codes, but it looks
>>> like something is wrong with the valueof
>>> section->offset_within_address_space? Thanks
>> It's ok since we need offset inside the region as the second parameter
>> of memory_region_set_dirty().
>>> [1]
>>> diff --git a/hw/vhost.c b/hw/vhost.c
>>> index 8d41fdb..785e68e 100644
>>> --- a/hw/vhost.c
>>> +++ b/hw/vhost.c
>>> @@ -55,7 +55,7 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
>>> ffsll(log) : ffs(log))) {
>>> ram_addr_t ram_addr;
>>> bit -= 1;
>>> - ram_addr = section->offset_within_region + bit *
>>> VHOST_LOG_PAGE;
>>> + ram_addr = addr + bit * VHOST_LOG_PAGE - section->mr->ram_addr;
>>> memory_region_set_dirty(section->mr, ram_addr, VHOST_LOG_PAGE);
>>> log &= ~(0x1ull << bit);
>>> }
>>>
>>>
>
> OK I think now I get it.
> The following should be the real thing.
>
>
> diff --git a/hw/vhost.c b/hw/vhost.c
> index dbf6b46..2d8ead8 100644
> --- a/hw/vhost.c
> +++ b/hw/vhost.c
> @@ -53,10 +53,14 @@ static void vhost_dev_sync_region(struct vhost_dev *dev,
> log = __sync_fetch_and_and(from, 0);
> while ((bit = sizeof(log) > sizeof(int) ?
> ffsll(log) : ffs(log))) {
> - ram_addr_t ram_addr;
> + hwaddr page_addr;
> + hwaddr section_offset;
> + hwaddr mr_offset;
> bit -= 1;
> - ram_addr = section->offset_within_region + addr + bit *
> VHOST_LOG_PAGE;
> - memory_region_set_dirty(section->mr, ram_addr, VHOST_LOG_PAGE);
> + page_addr = addr + bit * VHOST_LOG_PAGE;
> + section_offset = ram_addr - section->offset_within_address_space;
Should be page_addr here.
> + mr_offset = section_offset + section->offset_within_region;
> + memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE);
> log &= ~(0x1ull << bit);
> }
> addr += VHOST_LOG_CHUNK;
>
>
>
I get segfault with this patch, and looks like we need to check whether
the regions are overlapped in the begining of vhost_dev_sync_region:
if (!ranges_overlap(start, end - start + 1,
section->offset_within_address_space,
section->size)) {
return;
}
With this, no segfault and I can not reproduce the issue again.
- Re: [Qemu-devel] scp during migration with vhost fails, (continued)
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/20
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/20
- Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/21
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/21
- Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/22
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/23
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/23
- Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/25
- Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/25
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/25
- Re: [Qemu-devel] scp during migration with vhost fails,
Jason Wang <=
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/26
- Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/26
- Re: [Qemu-devel] scp during migration with vhost fails, Michael S. Tsirkin, 2013/02/25
Re: [Qemu-devel] scp during migration with vhost fails, Jason Wang, 2013/02/21